Like all human activities, scientific research is infused with values. Scientific discovery can, for example, be valued as an end in itself. The phrase ethical values is an umbrella term for much of what people care about aside from knowledge for its own sake. Ethical values encompass reasons for caring about the harms caused by climate impacts or the injustice of how those harms are distributed. The closer that research gets to informing real-world actions, the more the design of that research can be examined from the perspective of ethical values. Which societal challenges does the research aim to inform? From whose perspective does a policy analysis view potential outcomes? In this chapter we use a series of examples to illustrate how researchers’ choices regarding the treatment of uncertainties can have important consequences from the perspective of ethical values. Our aims in this chapter are to: familiarize readers with the key concept of coupled ethical–epistemic choices; build capacity for recognizing such choices within the treatment of uncertainties; encourage engagement with ethical values as a part of climate change research; and offer some guidance on how to start doing so.